Show notification app_name for Other notifications

## Problem

Notifications listed in the Other section are difficult to identify, especially if we fail to determine an appropriate icon. My screenshot doesn't capture this well due to this all being a single application, but imagine there were multiple apps here.


## Proposal

Notifications provide an `app_name` that represents the sending application.
The Other section of the notification indicator only shows icon, body, and summary.
Should we consider adding the app name to notifications in this section to better identify them?

## Prior Art

I'm not sure of any prior art or where other desktop environments group applications in an "Other" section.